70 receptions seems very optimistic to me.
Since 2000 these are the RB who had 50 receptions or more in their rookie seasons:
LaDanian Tomlinson 74 targets 59 receptions.
Reggie Bush 121 targets 88 receptions.
Christian McCaffrey 113 targets 80 receptions.
Tariik Cohen 71 targets 53 receptions.
Duke Johnson 74 targets 61 receptions.
Guivanni Bernard 71 targets 56 receptions.
Thats it. I think 70 targets could be in the cards but not 70 receptions.
This list is way off. There are actually 16 players who did it. Based on this data, i would say that is probably a 50% chance at least one RB in this rookie class gets at least 50 receptions in 2020. Now that being said, CEH is probably the most likely but I would maintain that it would not be that surprising if it were Gibson.
Games Receiving
Rk Player Year Age Draft Tm Lg G GS Tgt Rec Yds Y/R TD Y/G Ctch% Y/Tgt
1 Saquon Barkley 2018 21 1-2 NYG NFL 16 16 121 91 721 7.92 4 45.1 75.2% 5.96
2 Reggie Bush 2006 21 1-2 NOR NFL 16 8 121 88 742 8.43 2 46.4 72.7% 6.13
3 Alvin Kamara 2017 22 3-67 NOR NFL 16 3 100 81 826 10.20 5 51.6 81.0% 8.26
4 Christian McCaffrey 2017 21 1-8 CAR NFL 16 10 113 80 651 8.14 5 40.7 70.8% 5.76
5 Matt Forte 2008 23 2-44 CHI NFL 16 16 76 63 477 7.57 4 29.8 82.9% 6.28
6 Nyheim Hines 2018 22 4-104 IND NFL 16 4 81 63 425 6.75 2 26.6 77.8% 5.25
7 Edgerrin James* 1999 21 1-4 IND NFL 16 16 82 62 586 9.45 4 36.6 75.6% 7.15
8 Duke Johnson 2015 22 3-77 CLE NFL 16 7 74 61 534 8.75 2 33.4 82.4% 7.22
9 LaDainian Tomlinson* 2001 22 1-5 SDG NFL 16 16 74 59 367 6.22 0 22.9 79.7% 4.96
10 Jahvid Best 2010 21 1-30 DET NFL 16 9 80 58 487 8.40 2 30.4 72.5% 6.09
11 Giovani Bernard 2013 22 2-37 CIN NFL 16 0 71 56 514 9.18 3 32.1 78.9% 7.24
12 Tarik Cohen 2017 22 4-119 CHI NFL 16 4 71 53 353 6.66 1 22.1 74.6% 4.97
13 Kareem Hunt 2017 22 3-86 KAN NFL 16 16 63 53 455 8.58 3 28.4 84.1% 7.22
14 Trent Richardson 2012 22 1-3 CLE NFL 15 15 70 51 367 7.20 1 24.5 72.9% 5.24
15 Miles Sanders 2019 22 2-53 PHI NFL 16 11 63 50 509 10.18 3 31.8 79.4% 8.08
16 Steve Slaton 2008 22 3-89 HOU NFL 16 15 59 50 377 7.54 1 23.6 84.7% 6.39